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Faro
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Aural Glideslope High/Low Indication

Thu Jul 21, 2011 10:34 am

For the most sensitive parameter of the most sensitive phase of flight, glidescope tracking on approach, how about an aural indication of high/low position via the gizmo demonstrated in gliders in the first 30 seconds of the following video:

http://www.youtube.com/watch?v=jRSPj4WkTp0

In the glider video the aural indication (high/low tone) indicates positive or negative rate of climb; conceivably, it may also be wired to indicate vertical deviation (in distance or angle) above/below glidescope.

Advantages include freeing the pilot from frequent eyeballing of the PFD for this critical information and an intuitive "feel" for where he sits on the glidescope no matter what his eyes are doing on approach. In a nutshell, a tighter, crisper, more sensitive feedback loop between pilot action and instrument (aural) indication.

Faro

[Edited 2011-07-21 04:06:11]
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Goldenshield
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RE: Aural Glideslope High/Low Indication

Thu Jul 21, 2011 11:22 am

Quoting faro (Thread starter):
In the glider video the aural indication (high/low tone) indicates positive or negative rate of climb; conceivably, it may also be wired to indicate vertical deviation (in distance or angle) above/below glidescope.

The variometer is there to keep the pilot's eyes out the window, and used to indicate rising air. In sink, there is no sound.

All in all, an interesting idea, but then again, not practical in that form. However, an aural glideslope already exists---in the GS portion of the ILS, except that we can't hear it. Both the localizer and glideslope are based on old technology use for naviation: The Low Frequency Radio Range. And in action: www.youtube.com/watch?v=p-VqtNY8vpw .

edit:

Interestingly, the Silverlake LFR mentioned in the Wiki article, while not in commission, still exists partially where two of the original towers are still standing to this day, I'm thinking due to their proximity to the high-tension power lines that run right through the land, taking the towers down would be risky business.

[Edited 2011-07-21 04:50:12]
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wilco737
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RE: Aural Glideslope High/Low Indication

Thu Jul 21, 2011 11:32 am

Quoting faro (Thread starter):

If you are too low on the glideslope you get an aural warning "GLIDESLOPE". That gives you an idea that you are well too low. For too high there is no aural warning.

I don't know if I want such a feature. If you are established with gear and flaps on the glideslope and you are flying manual, you have a pitch and power value which will keep you on the glideslope in calm conditions. You have to crosscheck all the instruments anyway. So you look inside for speed, V/S, altitude; G/S, LOC, then you look outside to the runway, inside again etc etc. So if you have that aural warning then it shows you only if you are descending or climbing. But I need a whole lot more information during the approach. A simple town telling me that I am descending is not enough. I need to know how much I am descending (the rate)... So I have to crosscheck the instruments very often.

My instructor always said: "Dude, keep your eyes moving!" 

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26point2
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RE: Aural Glideslope High/Low Indication

Thu Jul 21, 2011 12:41 pm

What's wrong with "glideslope, glideslope", "GLIDESLOPE, GLIDESLOPE"?

EGPWS has a "Disable" to cancel the warning if the intent is to fly below GS....in types I have flown at least.

[Edited 2011-07-21 05:46:53]

[Edited 2011-07-21 05:49:55]
 
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Faro
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RE: Aural Glideslope High/Low Indication

Thu Jul 21, 2011 1:49 pm

Quoting 26point2 (Reply 3):
What's wrong with "glideslope, glideslope", "GLIDESLOPE, GLIDESLOPE"?

EGPWS has a "Disable" to cancel the warning if the intent is to fly below GS....in types I have flown at least.

Nothing really but it doesn't mean it can't be improved upon, and you don't presumably get "glidescope,glidescope" if you are above the slope, which is not desirable either. Wouldn't it be better to have:

- On glidescope: No tone at all;
- Above glidescope: low-pitch tone getting lower;
- Below glidescope: high-pitch tone getting higher; and
- Rate of change of tone also gives aural V/S trend.

What I like about it is that it is i) continuously perceivable, ii) uses the aural faculty which is pretty under-utilised in this phase of flight and iii) gives you a good indication about your most critical flight parameter in the approach -along with airspeed- as well as a V/S trend.

Faro
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wilco737
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RE: Aural Glideslope High/Low Indication

Thu Jul 21, 2011 2:10 pm

Quoting faro (Reply 4):

Did you read anything from what I posted above at all?

I have to do checks on ALL flight parameters, not only if I am on glideslope (not glidescope) or not... A tone for them all?!   

wilco737
  
 
wilco737
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RE: Aural Glideslope High/Low Indication

Thu Jul 21, 2011 2:12 pm

Quoting faro (Reply 4):

Did you read anything from what I posted above at all?

I have to do checks on ALL flight parameters, not only if I am on glideslope (not glidescope) or not... A tone for them all?!   

wilco737
  
 
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Faro
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RE: Aural Glideslope High/Low Indication

Thu Jul 21, 2011 4:11 pm

Quoting wilco737 (Reply 6):
Quoting faro (Reply 4):
Did you read anything from what I posted above at all?

I have to do checks on ALL flight parameters, not only if I am on glideslope (not glidescope) or not... A tone for them all?!   

wilco737

I did indeed Wilco   and am not suggesting that they *all* be toned indications, just the glidescope indication, otherwise the flightdeck would be a zoo. I understand that an instrument scan includes all flight parameters and not just G/S; my suggestion is simply to lighten up the eyeballing a bit via continuous resonance of high/low tone for one flight parameter only. In the end it's the end-user who decides of course on whether this is adding to or detracting from an efficient flight path control. Just another a.nut idea...

Faro
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pilotpip
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RE: Aural Glideslope High/Low Indication

Thu Jul 21, 2011 5:11 pm

There are already a ton of aural warnings. The 170 also puts a visual warning on the PFD in addition to the aural warning.

We're pretty alert on landing. On the 170 we have the Glideslope indication on the PFD, the aural warning, the Vertical profile on the MFD, and outside at most airport we have a VASI/PAPI.

How much more do you need? The last thing I want/need is a tone that makes it more difficult to keep situational awarenes by drowning out ATC and my captain. Not to mention the fatigue that the noise would cause.
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ThirtyEcho
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RE: Aural Glideslope High/Low Indication

Thu Jul 21, 2011 5:17 pm

Why complicate things unnecessarily? An aural indication for the glideslope is not at all needed and is potentially confusing at a time when instrument cross check is at its peak.

If we take the simple example of a sturdy old 172, very few things are needed to "nail" the glideslope all the way down. If the intercept is made at 90kts with 1900RPM, dropping to about a 700fpm descent is going to put you right on the sucker. Adjusting for updrafts and downdrafts is needed but, in normal conditions, if you stay on profile tracking the glideslope isn't very difficult. Excursions from this profile lead to chasing the needle which leads to wider excursions, etc., etc..

With more complex aircraft, gear and flaps are going to change the profile but this is easily learned with a few hours in type.

I can say that, having flown a few 4-course ranges in my time, making a mental picture of any aural guidance system (except for caution/emergency warnings) is a difficult art that can lead to far larger deviations than visual guidance.

[Edited 2011-07-21 10:23:41]
 
rwessel
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RE: Aural Glideslope High/Low Indication

Fri Jul 22, 2011 5:09 am

Quoting Goldenshield (Reply 1):
The variometer is there to keep the pilot's eyes out the window, and used to indicate rising air. In sink, there is no sound.

Every audio variometer I've ever flown with has done tones on both the uphill (high pitched and increasing) and downhill (low pitch and decreasing) side of things. Often it's more a continuous tone on the plus side, and a buzzing on the minus side. Often there's a silent band around the zero-lift sink rate.

Given the number of options* on many of these things, it's perhaps possible to turn off the audio on the sink side, although I'm not sure why you'd want to do that - while I like knowing when I hit lift, I *really* like knowing when I hit sink.


*A friend of mine was going on the other day about a vario (+GPS) he's considering that apparently will give you centering hints by using stereo speakers, and sending the sound one way or the other... Makes me wonder. I remember many happy hours beating around in a 1-26 whose only semi-reliable instrument was the compass (the static system was trashed**, and you could significantly vary your airspeed and altitude by slipping the thing or fiddling with the vents - we left the audio on the vario off most of the time - at least when the battery wasn't dead). And the compass was no great shakes either, unless you were straight and level. IOW: Kids these days!   

**Ultimately we pulled all the tubing for the pitot/static system (we didn't really care all that much***, but we were pretty board one day) - the tube to the static port on one side had a slug of water in it, and the tube to the other side had a cut and was partially open to the cabin.

***After all, it was a 1-26, it's not like hyper-accurate instruments are going to make much a difference on a 23:1**** ship.

****Now there’s a bit of optimism for ya!
 
Mir
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RE: Aural Glideslope High/Low Indication

Fri Jul 22, 2011 7:49 am

Quoting faro (Thread starter):
Advantages include freeing the pilot from frequent eyeballing of the PFD for this critical information

Remember that an ILS is an instrument maneuver - if you're in the clouds, the pilot's eyes should be on the PFD anyway, as that's the only way he can fly the airplane. And if you're not in the clouds and the pilot can see the runway, they shouldn't need to be looking at the PFD all that much to maintain a constant glidepath with reasonable accuracy - eyes should be mostly outside, with glances down to check the instruments every so often.

Basically, you seem to be trying to solve a problem that doesn't exist. Also, this would be a big nuisance on approaches where the pilot can see the runway - it's better to fly a glidepath that is consistently a bit off rather than trying to get the glideslope exactly right, and as a result undershooting and overshooting (and thus triggering the tones).

-Mir
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tdscanuck
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RE: Aural Glideslope High/Low Indication

Fri Jul 22, 2011 7:51 am

Quoting faro (Reply 4):

What I like about it is that it is i) continuously perceivable,

So's the glideslope indication...if you're shooting an ILS and you actually need that precision, you're heads-down and you're watching the indications anyway. If you're using the ILS in VFR, you should be heads up anyway and flying visual. Glideslope indications when you're not actually flying the ILS would just be distracting.

Quoting faro (Reply 4):
ii) uses the aural faculty which is pretty under-utilised in this phase of flight

That's intentional...you suppress aurals in critical phases of flight to only those that require immediate pilot action to avoid distraction.

Quoting faro (Reply 4):
iii) gives you a good indication about your most critical flight parameter in the approach -along with airspeed- as well as a V/S trend.

Glideslope tracking isn't your most critical flight parameter...not sure why you'd fix on that as the one to put the aural tone on.

Tom.
 
Goldenshield
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RE: Aural Glideslope High/Low Indication

Fri Jul 22, 2011 11:51 am

Quoting rwessel (Reply 10):
Every audio variometer I've ever flown with has done tones on both the uphill (high pitched and increasing) and downhill (low pitch and decreasing) side of things. Often it's more a continuous tone on the plus side, and a buzzing on the minus side. Often there's a silent band around the zero-lift sink rate.

The ones I've flown with only have an up band. They do have a low side, but they only sound when the vario hits greater than zero. Perhaps these are just older models, though, or perhaps they are just set up this way. I've only flown one ship that is not a club ship, and since they are club ships, it's not like I can mess with how they are set up. However, that said, looking at WingandWheels really quick, there are at least 7 different manufacturers of varios, and each will most likely have "their own way of doing it."

I've got an audio vario in my private ship with zero documentation, and googling has turned up no answers, so, I just leave it as is. Granted, this model hasn't been made since like 1979, so I would expect support and documentation to be lacking.
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Woodreau
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RE: Aural Glideslope High/Low Indication

Fri Jul 22, 2011 11:52 am

One instrument if I was required to have an audible indication of would be the AOA indicator. Granted I haven't been in a lot of aircraft that had one but I think that is probably more useful than the airspeed indicator on approach.
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pilotpip
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RE: Aural Glideslope High/Low Indication

Fri Jul 22, 2011 10:52 pm

Quoting woodreau (Reply 14):
One instrument if I was required to have an audible indication of would be the AOA indicator. Granted I haven't been in a lot of aircraft that had one but I think that is probably more useful than the airspeed indicator on approach.

They have that, it's called a stall warning system.

If AOA was so important (beyond critical), I would have an AOA indication. Oddly enough, I don't. I do, however, have an airspeed indicator.
DMI
 
FredT
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RE: Aural Glideslope High/Low Indication

Fri Jul 29, 2011 5:46 pm

Quoting pilotpip (Reply 15):
If AOA was so important (beyond critical), I would have an AOA indication. Oddly enough, I don't. I do, however, have an airspeed indicator.

But you have a speedbook, right?

And what is that, exactly? Yes, a rather oblique way of making sure you are at roughly the right AoA on the approach...

I find it amazing that AoA indicators are not mandated in airliners. The sensor is there, and AoA is one of the most interesting parameters if you know what to do with it, but yet the indicators are typically not installed in civilian aircraft.

If someone tells me it is not interesting, I'll bring up AF447 and throw a stack of speedbooks at you. You've been warned.

Cheers,
Fred
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Mir
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RE: Aural Glideslope High/Low Indication

Fri Jul 29, 2011 10:04 pm

Quoting FredT (Reply 16):
If someone tells me it is not interesting, I'll bring up AF447

I doubt that AF447 would have been prevented by having an AoA indicator. The problem with AF447 is that they didn't trust their instrumentation - all the information they needed was there, but they weren't able to use it (or didn't think it was useful). I suspect that an AoA indicator would have just been one more thing that they either unintentionally or intentionally ignored. We already know they ignored the stall warning, which is a form of AoA indicator.

-Mir
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